Given a set of candidate numbers (C) (without duplicates) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.
The same repeated number may be chosen from C unlimited number of times.
Note:
All numbers (including target) will be positive integers.
The solution set must not contain duplicate combinations.
For example, given candidate set [2, 3, 6, 7] and target 7,
A solution set is:
[
[7],
[2, 2, 3]
]public List<List<Integer>> combinationSum(int[] candidates, int target) {
int length = candidates.length;
Arrays.sort(candidates);
List<List<Integer>> results = new ArrayList<>();
helper(candidates,results,target,0,new ArrayList<>());
return results;
}
public void helper(int[] candidates,List<List<Integer>> results,int target,int index,List<Integer> curr){
if (target==0){
ArrayList<Integer> item = new ArrayList<>();
item.addAll(curr);
results.add(item);
return;
}
for (int i=index;i<candidates.length;i++){
if (target>=candidates[i]){
curr.add(candidates[i]);
helper(candidates,results,target-candidates[i],i,curr);
curr.remove(curr.size()-1);
}
}
}